Surface pumps are used in a variety of applications for raising liquid from a well or borehole to surface level. For example such pumps may be used to provide drinking water to communities, particularly in the developing world, with lever-action reciprocating handpumps such as the Afridev pump or India Mark II being the most common types. Onshore oil deposits where the deposit does not create sufficient pressure to drive oil to the surface may also use a piston pump (for example of the nodding donkey type) to raise oil to the surface.
The maintenance of such pumps in the field present challenges because the network of pumps in use is often distributed over large regions sometimes with insufficient local capacity for timely repairs. In the case of hand operated water pumps, although they offer significant benefits over open wells by providing a high discharge rate and avoiding the health problems associated with open wells, it can be difficult to arrange for local maintenance and repair and the health, economic and time consequences of a pump becoming inoperable are serious for the local community. Although the same social issues do not arise with surface pumps in oil fields, nevertheless providing for efficient maintenance and avoiding down time is still economically important.
In 2012 a “smart hand pump” was developed and tested in sub-Saharan Africa. This was based on the incorporation of a consumer-grade, low-cost IC-based accelerometer, such as those found commonly in mobile phone handsets and games controllers, enclosed in an inexpensive waterproof container and securely fitted into or onto the handle of a standard hand pump. The accelerometer was connected to a low power microprocessor programmed to estimate from the accelerometer output signal by measuring the number of pumping strokes and the range of pump movement. The data acquired was then automatically transmitted over the domestic mobile telecommunications network as an SMS text message to a control server which allowed identification of the location of the pumps and an indication of the usage patterns of any individual pump. While usage data was, in itself, of interest, the monitoring of usage also allowed the detection of inoperable pumps so that a maintenance team could be dispatched.
Although the smart hand pump was a useful step forward, it only provided crude usage data and could only alert to a faulty pump after it had become inoperable or unused, or a major fault had developed.
As surface pumps are used to access underground resources, it is always of interest to monitor the level of those resources. For example, in the case of water supply it is important to monitor the aquifer level in order that adequate supply for the community can be ensured in the long term, or because lowering aquifer levels are associated with increased salinity or higher concentrations of undesirable elements or compounds. In the case of an oil field, monitoring the level of oil allows the productivity and lifetime of the field to be monitored. Traditionally such monitoring is achieved by disposing a sensor down the well or borehole, for example an electrical conductivity sensor. This can be done on an occasional basis (as “dipping the well”), or in some cases level sensors can be permanently disposed in the well. It is expensive, however, to provide permanent level sensing in wells, and retrofitting level sensing, especially in the case of water wells, can risk damaging the integrity of the well and potentially contaminating it. Providing sensors capable of automated operation and which can be remotely monitored is also expensive.